Re: Transpose matrix does not work when MatrixForm is used, why?

*To*: mathgroup at smc.vnet.net*Subject*: [mg45599] Re: Transpose matrix does not work when MatrixForm is used, why?*From*: drbob at bigfoot.com (Bobby R. Treat)*Date*: Fri, 16 Jan 2004 06:05:16 -0500 (EST)*References*: <bu0cdt$agi$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I doubt that most of us want ALL rectangular lists displayed as matrices. I certainly don't. Bobby Paul Abbott <paul at physics.uwa.edu.au> wrote in message news:<bu0cdt$agi$1 at smc.vnet.net>... > In article <bsoe80$en3$1 at smc.vnet.net>, Dr Bob <drbob at bigfoot.com> > wrote: > > > No, Andrzej's solution works much better. That way I get to see m in > > MatrixForm every time it is displayed... and still do math with it. > > > > Unprotect[MatrixForm]; > > MatrixForm /: > > (f_)[MatrixForm[expr_, > > opts___]] := MatrixForm[ > > f[expr], opts] > > Protect[MatrixForm]; > > m = MatrixForm[{{1, 2, 3}, > > {4, 6, 5}, {9, 8, 7}}] > > m > > Transpose[m] > > Inverse[m] > > > > His solution isn't complete, as this doesn't work yet: > > > > m.Inverse[m] > > > > This takes care of that: > > > > Unprotect[MatrixForm]; > > MatrixForm /: f_[MatrixForm[a_], MatrixForm[b_]] := MatrixForm[f[a, b]] > > Protect[MatrixForm]; > > > > But then this still doesn't work: > > > > m.m.m > > > > But this does: > > > > (m.m).m > > > > The behavior I want is nothing more than what Help says is already there > > -- MatrixForm shouldn't affect evaluation. > > If you set your set your Default Output FormType to TraditionalForm then > matrices are automatically displayed as such and everything works as you > require. If you don't want to do this, you can just set things up so > matrices are displayed in TraditionalForm as follows. > > $PrePrint := If[MatrixQ[#] == True, TraditionalForm[#], #] & > > Earlier you wrote that > > > > I don't want to see EVERY matrix in MatrixForm -- it takes up too much > > > space on my screen, especially for a large matrix, where the screen isn't > > > even wide enough to see a row in that format. > > You may find MatrixPlot in LinearAlgebra` useful here. > > Cheers, > Paul